WHITE PAPER

The success of your research depends on the quality of your starting materials. At ABS Bio, we draw on more than 25 years of experience growing and evaluating hundreds of cell lines to ensure that foundation is solid. In this article, we share the key quality control (QC) checks we perform every day—some designed to catch the silent threats that can derail experiments, others to provide the rigorous quantitative data your work demands.

Below is a checklist of core quality control procedures that every cell culture laboratory should implement—these are the same steps we rely on at ABS Bio to ensure the integrity and reproducibility of our work:

1. Confirm experimental protocols – Verify that study plans and SOPs are correctly followed before initiating work.
2. Validate growth conditions – Confirm media composition, seeding densities, and other culture conditions are correct.
3. Quarantine and pre-myco screening – Isolate new or incoming cell lines and perform preliminary mycoplasma testing.
4. Pre-banking assessment – Measure cell counts and viability before freezing.
5. Post-freeze evaluation – Reassess cell counts and viability of banked vials after thawing.
6. Sterility testing – Screen banks for bacterial and fungal contamination.
7. Mycoplasma testing – Conduct thorough post-banking mycoplasma testing to ensure long-term culture integrity.

When ABS Bio receives a client’s cell line, we first perform a post-thaw cell count and assess viability. Before any final freeze-down or additional processing—such as preparing cell pellets or membranes—we conduct further counts to document total cell numbers, concentrations, and viability. For cryopreserved lines, we also reserve vials for a later thaw to confirm that post-freeze counts and viability meet the client’s specifications.

All cell banks must be contamination free, so sterility testing for mold and bacteria contamination is done for all banks post freeze. To ensure no cross-contamination between projects, media and other reagents for specific client orders are kept separate from each other.

Contamination of human cell lines by animal cells may be examined using PCR. Various viral panels may be run if specified. At our clients’ request, we provide information on cell doubling times, percent confluence, and photomicrographs of cell in culture.

MYCOPLASMA AND CELL LINE MISIDENTIFICATION
Two hidden threats can quietly undermine your research, and the most common is mycoplasma contamination. Even in well-run laboratories, occasional contaminations can occur. Mycoplasma can subtly alter cell growth and gene expression, often without visible signs. To protect against this risk, ABS Bio tests for mycoplasma both upon receipt of client cells and before any cells leave our facility. Our proprietary PCR-based assay delivers rapid, highly sensitive detection, ensuring confidence in your cultures.

The second major risk to research integrity is cell line misidentification. This problem typically stems from two sources: (1) labeling discrepancies and (2) receiving the wrong cell line altogether. At ABS Bio, we address the first risk as soon as a shipment arrives by verifying that every vial label matches the accompanying manifest. In practice, it’s common for the same cell line to be labeled inconsistently by different technicians—or for related lines, such as variants with specific receptor or ion channel subtypes, to have nearly identical names. We make no assumptions, and any inconsistencies are promptly clarified with our clients to ensure absolute accuracy.

Once shipping manifests are reconciled, all cell vials are logged into our secure tracking system for temporary storage, maintaining a strict chain of custody. While this level of tracking may seem meticulous, the stakes are high—one mislabeled vial can derail an entire screening campaign. We’ve seen how costly such mistakes can be, and our goal is to ensure they never happen to you or to us.

To address the second cause of cell line misidentification, cell line authentication provides unambiguous identification of each sample. ABS Bio delivers detailed data that uniquely identifies your human cell line or tissue sample by:

• Analyzing 15 Short Tandem Repeats (STRs) and X/Y chromosome markers from minute quantities of DNA
• Generating a unique cell line profile for your sample
• Cross-checking that profile against a comprehensive database of known cell lines

In our experience, misidentification is rare with cell lines sourced from major pharmaceutical and biotechnology clients, but the cost of authentication is minimal compared to the potential losses of using the wrong line.

Protein Expression and Localization
Protein expression can be assessed using RT-qPCR or Western blot analysis, while phenotypic expression may be evaluated through flow cytometry or immunocytochemistry (ICC) on prepared histogels. Monitoring protein target localization often provides critical insights; for example, a membrane protein may be produced in high quantities but fail to reach the cell surface due to aberrant post-translational modifications in a particular line.